1. Field of the Invention
The present invention relates to an organic electroluminescent display device, and more particularly, to an organic electroluminescent device and a method of driving the same.
2. Discussion of the Related Art
Until recently, display devices have typically used cathode-ray tubes (CRTs). Presently, many efforts and studies are being made to develop various types of flat panel displays, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission displays, and organic electroluminescent display (OELD) devices, as a substitute for CRTs. Of these flat panel displays, OELD devices have many advantages, such as low power supply, thin profile, wide viewing angle light weight, and fast response time.
In general, among the OELD devices, an active matrix type OELD is widely used. The OELD device display images by applying a current to an organic light emitting diode in each pixel and emitting light from the organic light emitting diode.
In operating the organic light emitting diode, when a thin film transistor using an amorphous silicon is employed, a current continues to be supplied to the organic light emitting diode. Accordingly, reduction of brightness and continuous stress due to shift of threshold voltage causes lifetime of the thin film transistor to be reduced.
To solve the problems, a structure using dual thin film transistors is suggested. In this structure, an image data and a refresh data (e.g., a data for a negative voltage or black data) are alternately applied to one and the other of the dual thin film transistors. Accordingly, reduction of stress and increase of lifetime of thin film transistor are achieved.
However, according to a sequence of applying the image data and refresh data, an overall screen may flash, and thus display quality is degraded.